Changed the test to accept all the retrievers as its not licensed

Author: mridula-s109

x-pack/plugin/search-business-rules/src/test/java/org/elasticsearch/xpack/searchbusinessrules/retriever/PinnedRetrieverBuilderTests.java

@@ -67,7 +67,7 @@ protected PinnedRetrieverBuilder doParseInstance(XContentParser parser) throws I
             parser,
             new RetrieverParserContext(
                 new SearchUsage(),
-                nf -> false
+                nf -> true
             )
         );
     }